Definition of Syncope, situational

Syncope, situational: The temporary loss of consciousness
in a particular kind of situation. The situations that trigger this
reaction are diverse, and include having blood drawn, straining while
urinating or defecating, and coughing. It can also be due to the
emotional stress, fear, or pain. When experiencing the trigger
condition, the person often becomes pale and feels nauseated, sweaty,
and weak just before losing consciousness. Situational syncope is
caused by a reflex of the involuntary nervous system called the
vasovagal reaction. The vasovagal reaction leads the heart to slow
down (bradycardia), and at the same time it leads the nerves that
serve the blood vessels in the legs to permit those vessels to dilate
(widen). The result is that the heart puts out less blood, the blood
pressure drops, and circulating blood tends to go into the legs
rather than to the head. The brain is deprived of oxygen, and the
fainting episode occurs.

Situational syncope is also known as
vasovagal syncope, vasodepressor syncope, and Gower syndrome. See
also syncope, vasovagal reaction.